PNG loses transparency when merging with image()

Thursday 25 March 2010 11:55:31 am

I have two transparent PNGs and I want to merge them into one transparent PNG using the image() operator. But it doesn't work, the resulting image looses transparency and is converted to black and white. This is the code I use:

{image(

 imagefile( 'design/dev/images/image1.png'),

 array(

  imagefile( 'design/dev/images/image2.png' ) ,

  hash(

    halign, left,

    valign, top

  ) 

 )

)}

Am I doing something wrong, or the problem is in eZ?

This could be related to this forum post:

http://share.ez.no/forums/developer/png-image-resize-loose-transparency

and this issue:

http://issues.ez.no/IssueView.php?Id=15640

Can someone confirm this is a bug in eZ?

P.S. I'm using eZ 4.1.4

--
Nothing is impossible. Not if you can imagine it!

Hubert Farnsworth

Friday 17 June 2011 8:23:33 am

This message gave me idea
 http://stackoverflow.com/questions/32243/can-png-image-transparency-be-preserved-when-using-phps-gdlib-imagecopyresampled

And i made small changes in ezimagegdhandler.php:
 i added

    imagealphablending( $temporaryImageObject, false );    imagesavealpha( $temporaryImageObject, true );

 after

       $temporaryImageObject = eZImageGDHandler::imageCreate( $destinationWidth, $destinationHeight, eZImageGDHandler::isImageTrueColor( $imageObject, $sourceMimeData ) );

It saves PNG transparency before resizing.

I made patch, if someone is interested. http://issues.ez.no/IssueView.php?Id=15640&activeItem=1

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